Texture space shading and reconstruction for ray tracing

Abstract

An apparatus and method are described for texture space shading. For example, one embodiment of a method comprises: performing texture mapping to map one or more textures to surfaces of one or more objects in texture space within a ray tracing architecture; and performing sampling and reconstruction directly on the surfaces of the objects in the texture space.

What is claimed is: 
     
       1. A method comprising:
 performing texture mapping to map one or more textures to surfaces of one or more objects in texture space within a ray tracing architecture; and 
 performing sampling and reconstruction directly on the surfaces of the objects in the texture space to generate filtered texture-mapped object data, wherein performing sampling and reconstruction further comprises:
 sampling and caching individual texels and/or groups of texels; and 
 when all texels under a footprint of a reconstruction filter kernel are available from a cache, evaluating the reconstruction filter, and caching a resulting color for later reuse to a per-face texture, the texels under the footprint including currently visible and currently not visible texels, 
 
 wherein reconstruction directly on the surfaces of the objects removes noise from the objects in the texture space; and 
 wherein sampling and reconstruction is triggered and cached within the footprint of the reconstruction filter. 
 
     
     
       2. The method as in  claim 1  wherein performing sampling and reconstruction further comprises:
 querying a texel shading cache to determine whether a current texel has been shaded; 
 if the current texel has not been shaded then computing a filter footprint and querying a sample shading cache for each sample within the filter footprint to determine whether each sample has been previously shaded; 
 using the sample from the sample shading cache if the sample has been previously shaded or shading the sample if it has not been previously shaded and storing the shaded sample in the sample shading cache; and 
 when all texels under a footprint of a reconstruction filter kernel are shaded, evaluating the reconstruction filter, and caching the results in the texel shading cache for later reuse. 
 
     
     
       3. The method as in  claim 1  wherein the textures include one or more mip-maps. 
     
     
       4. The method as in  claim 3  wherein each mip-map comprises multiple levels of detail (LOD) to represent the textures. 
     
     
       5. The method as in  claim 1  further comprising:
 performing ray tracing-based based rendering on the filtered texture-mapped object data to generate a set of rendered image frames. 
 
     
     
       6. The method as in  claim 1  further comprising:
 parameterizing shading values as grids in a local uv-coordinate space of a current patch. 
 
     
     
       7. The method as in  claim 6  wherein when a filter extends beyond the current patch, adjacency information is used to locate texels from neighboring patches. 
     
     
       8. The method as in  claim 6 , wherein the grids are hierarchically organized as an image pyramid of shading values per face, which are lazily populated based on ray differentials on an incoming ray that trigged the texture mapping. 
     
     
       9. The method as in  claim 1  wherein each texel comprises a product sampling record (PSR), each PSR to be used for importance sampling. 
     
     
       10. The method as in  claim 9  wherein one or more of the PSRs are to be stored within a cache so as to be available on-demand in the texture space. 
     
     
       11. The method as in  claim 10  further comprising:
 retrieving and using the cached PSR to guide importance sampling for all direct illumination shading evaluations within a local footprint in texture space. 
 
     
     
       12. The method as in  claim 11  further comprising:
 computing a PSR identifier; 
 querying the cache using the PSR identifier to determine whether the PSR is stored therein; 
 if the PSR is stored in the cache, then mapping the PSR to the surfaces of one or more objects in texture space; and 
 if the PSR is not stored in the cache, then building the PSR and storing the PSR in the cache. 
 
     
     
       13. The method as in  claim 12  wherein building the PSR comprises:
 sampling a bidirectional scattering distribution function (BSDF) slice in a local footprint of a reconstruction filter kernel; and 
 using BSDF samples and an environment map to build the PSR. 
 
     
     
       14. An apparatus comprising:
 object/texture space circuitry to perform texture mapping to map one or more textures to surfaces of one or more objects in texture space within a ray tracing architecture; and 
 a shading and reconstruction filter to perform sampling and reconstruction directly on the surfaces of the objects in the texture space to generate filtered texture-mapped object data, wherein to perform sampling and reconstruction the shading and reconstruction filter further:
 samples and caching individual texels and/or groups of texels; and 
 when all texels under a footprint of a reconstruction filter kernel are available from a cache, evaluates the reconstruction filter, and caches a resulting color for later reuse to a per-face texture, the texels under the footprint including currently visible and currently not visible texels, 
 
 wherein reconstruction directly on the surfaces of the objects removes noise from the objects in the texture space; and 
 wherein sampling and reconstruction is triggered and cached within the footprint of the reconstruction filter. 
 
     
     
       15. The apparatus as in  claim 14  wherein performing sampling and reconstruction further comprises:
 querying a texel shading cache to determine whether a current texel has been shaded; 
 if the current texel has not been shaded then computing a filter footprint and querying a sample shading cache for each sample within the filter footprint to determine whether each sample has been previously shaded; 
 using the sample from the sample shading cache if the sample has been previously shaded or shading the sample if it has not been previously shaded and storing the shaded sample in the sample shading cache; and 
 when all texels under a footprint of a reconstruction filter kernel are shaded, evaluating the reconstruction filter, and caching the results in the texel shading cache for later reuse. 
 
     
     
       16. The apparatus as in  claim 14  wherein the textures include one or more mip-maps. 
     
     
       17. The apparatus as in  claim 16  wherein each mip-map comprises multiple levels of detail (LOD) to represent the textures. 
     
     
       18. The apparatus as in  claim 14  further comprising:
 ray-tracing-based rendering circuitry/logic to perform ray tracing-based based rendering on the filtered texture-mapped object data to generate a set of rendered image frames. 
 
     
     
       19. The apparatus as in  claim 14  wherein the shading and reconstruction filter is to parameterize shading values as grids in a local uv-coordinate space of a current patch. 
     
     
       20. The apparatus as in  claim 19  wherein when a filter extends beyond the current patch, adjacency information is used to locate texels from neighboring patches. 
     
     
       21. The apparatus as in  claim 14  each texel comprises a product sampling record (PSR), each PSR to be used for importance sampling. 
     
     
       22. The apparatus as in  claim 21  wherein one or more of the PSRs are to be stored within a cache so as to be available on-demand in the texture space. 
     
     
       23. The apparatus as in  claim 22  wherein the cached PSR is to be retrieved and used to guide importance sampling for all direct illumination shading evaluations within a local footprint in texture space. 
     
     
       24. The apparatus as in  claim 21  wherein the object/texture space circuitry and/or logic is to perform the operations of:
 computing a PSR identifier; 
 querying the cache using the PSR identifier to determine whether the PSR is stored therein; 
 if the PSR is stored in the cache, then mapping the PSR to the surfaces of one or more objects in texture space; and 
 if the PSR is not stored in the cache, then building the PSR and storing the PSR in the cache. 
 
     
     
       25. The apparatus as in  claim 24  wherein building the PSR comprises:
 sampling a bidirectional scattering distribution function (BSDF) slice in a local footprint of a reconstruction filter kernel; and 
 using BSDF samples and an environment map to build the PSR. 
 
     
     
       26. A system comprising:
 a memory to store data and program code; 
 a central processing unit (CPU) comprising an instruction cache for caching a portion of the program code and a data cache for caching a portion of the data, the CPU further comprising execution logic to execute at least some of the program code and responsively process at least some of the data, at least a portion of the program code comprising graphics commands; 
 a graphics processing subsystem to process the graphics commands and responsively render a plurality of image frames, the graphics processing subsystem comprising: 
 object/texture space circuitry and/or logic to perform texture mapping to map one or more textures to surfaces of one or more objects in texture space within a ray tracing architecture; and 
 a shading and reconstruction filter to perform sampling and reconstruction directly on the surfaces of the objects in the texture space to generate filtered texture-mapped object data, wherein to perform sampling and reconstruction the shading and reconstruction filter further:
 samples and caching individual texels and/or groups of texels; and 
 when all texels under a footprint of a reconstruction filter kernel are available from a cache, evaluates the reconstruction filter, and caches a resulting color for later reuse to a per-face texture, the texels under the footprint including currently visible and currently not visible texels, 
 
 wherein reconstruction directly on the surfaces of the objects removes noise from the objects in the texture space; and 
 wherein sampling and reconstruction is triggered and cached within the footprint of the reconstruction filter.